Printing cylinder



May 17, 1938. o. R. HuGGlNs PRINTING CYLINDER Filed oct. 19, 1935ATTORNEY Qww Way n Patented May 1,7, 1938 -1 UNITED .STATES PATENTOFFICE,

signor to Photo-Cylinder Corporation, afcorporation of New YorkApplication October 19, 1935, Serial No. u45,'10'1' I4 Claims.

This invention relates to methodsof, and means for salvaging spentprinting cylinders.

In general, a printing cylinder is made from copper, and in operation itis. forced over a ta- '5 pered mandrel, inked and then run over thematerial until the desired number of reproductions have been printedafter which it is forced from the-mandrel and then 'turnedl down andpolished to permit a new design to be etched onl tapered mandrelaverages approximately 511.500

inches, thus leaving a printing wall of approximately 0.796 inch. Inthis industry experience has taught that when the cylinder has beenturned Adown until the thickness. oi the printing wall is reducedn toappromately 0.588 inch` the cylinder must be scrapped with a consequentloss of more than twice the amount of copper than is actually usedduring the life of the cylinder.

Heretofore, many attempts have been made to salvage these spent printingcylinders by adding copper to the outer surface to build up thethickness of the printing wall to a desired value. In thus adding copperto the outer surface of the spent cylinder, however, considerableexpense is involved, and primarily for this reason it is still commonpractice to scrap the spent cylinders.

In accordance withthe present invention, a spent printing cylinder issalvaged, not by adding copper to its outer surface but by` expandingthe cylinder and then lining it with a relatively inexpensive metal oralloy, such as zinc. More Di A ` specifically, the spent printingcylinder is expanded until its outside diameter is substantially thesame as it was originally, and after the cylinder is so expanded it isprovided with a lining of relatively inexpensive metal through which amandrel hole extends of substantially the same size and shape as theoriginal mandrel hole, thus restoring the printing wall of the cylinderto its,

created during the printing operation or while p (Cl. lol-401.1)

polished -a number of times to permit new-designs to be etched n itsprinting surface without dan.-

ger of distortion during the printing operation or while the cylinderis' being forced onto lor ofi the mandrel. l

For a clear understanding of the present invention reference may be madeto the accompanying drawing wherein: I l Fig. 1 is an elevational View,'partially in section of aprinting cylinder;

Fig. 2 is an end view of the same;

Fig. 3 is a view, partially in section, showing a printing cylinder in amold, as well as the expander element used to expand'the cylinder;

Fig. 4 is a sectional view showing the cylinder expanded in the mold; Yy

Fig. 5 is a view, partially in section, showing the expanded cylinderprior to the formation of the lining therein;

Fig. 6 is a sectional view t 6-6 of Fig. 1; y

Fig. '7 is a sectional view of the expanded cylinder with the liningformed therein; and

Fig. 8 is a sectional view taken along the line 8-8 of Fig. 7.

As shown in Fig. 1, a printing cylinder I0 is provided with a taperedmandrel hole Il through which a key l2 extends,'the tapered mandrel holeil being provided to permit the cylinder lll to be easily forced ontoand ofi a tapered mandrel, and the key i2 being provided to guide thecylinder as it is being forced onto the mandrei as well as to preventdisplacement thereof after it is so mounted.

In practicing the present invention, a printing cylinder I0 of thissort,` after being turned down and polished a number of'times, issalvaged by expanding it to substantially its original outside di`-ameter, and to this end, as shown in Fig. 3, it is placed in a mold I3having an internal diameter vsubstantially the, same as the originaloutside diameter of the cylinder, and an expander 'element i4 is forcedtherethrough. The mold i3 is desirably made in sections so that itcan betaken apart to permit the expanded cylinder to` be easily removedtherefrom; and to prevent/:fdisplacement of the cylinder while it isbeing expanded the mold I3 is provided 'with an annular shoulder l5against which one end of the cylinder is positioned. The expanderelement I4 desirablyemployed is tapered throughout its length and it isprovided with a key way I6 which rides over the key l2 as the element Ilis forced through the cylinder soV that the original key I2 is preservedwhile the cylinder is being expanded and aken along the line theoriginal tapered mandrel hole is being enlarged and made uniformthroughout its length. In forcing the expander element I4 throughA thespent cylinder itis desirably forced through from the small end of theoriginal tapered mandrel hole and to this end the cylinder I@ is placedin the mold I3 with the end wherein the diameter of the mandrel hole IIis the greatest positioned against the shoulder I5 and the shoulder I5lnturn, is positioned against a suitable stop (not shown). through thecylinder I by any means, and as it is thus forced through the cylinderany excess copper is forced ahead to the other end thereof where it isremoved to restore the cylinder to its original length.

` After the spent cylinder has been thus expanded to substantially itsoriginal outside diameter a lining I'I is cast therein, and to this enelthe expanded cylinder is positioned vertically on a mold block I8, asshown in Fig. 5. and a core I9 is positioned therein. This core I9 isofsubstantially the same size as the original mandrel hole II and it has aslot which is of substantially the same size as the original key I2. Thecore I9 is centrally positioned within the expanded cylinder, preferablywith the big end of the coreat the bottom of thecylinder, and after itis so positioned the space between it and the inner surface of thecylinder is lled with molten metal which is poured through an opening 2Iin a retaining ring 22through which the upper end of the core I extends.The metal thus poured is allowed to harden after which the core isremoved thus providing a printing cylinder having an outer shell ofdistorted copper and a lining therefor of relatively inexpensiveAundistorted metal, and since the outside diameter of the copper shellis substantially the same as the outside diameter of the' originalcylinder and since the size and shape of the new mandrel hole in thelining issubstantially the same as the size and shape of the originalmandrel hole, the thickness of the printing wall of the salvagedcylinder is substantially the same as the thickness of the printing wallof the original cylinder. Under these conditions the salvaged printingcylinder may be mounted on a standard mandrel, and it may be turned downand polished a number of times to permit new designs to be etched on itsprinting surface.

In practicing the present invention it has been found that a better bondis obtained between the cylinder III and the lining l1 when the cylinderhas been heated before the lining is poured since when this is done thecylinder is expanded still further and as it cools it contracts intofirm engagement with the lining,

Also, in practicing the present invention it has been found desirable tobreak up the original key I2 as shown in Fig. 1, into a number of keysections 25, as shown in Fig. 4, by cutting a number of slots 26 thereinbefore the formation of the lining I1. Then, as the lining I1 is formed,the

key sections become embedded and serve to anchor the lining` I1 to thecylinder I0.

In the event the lining is formed from an extremely soft metal Yor alloyit may be desirable to Y provide means for protecting the lead end ofthe new key 24 to prevent it from being damaged as the salvaged cylinderis forced onto a mandrel, and when this protection is desired it may beobtained by positioning 'a short section of a preformed key 2l in thelower end of the slot 20 i n the core I9 before the lining II is formed.The

The expander element Id is then forced 2,1 raves then restoring theprinting wall of the cylinder to substantially its original thickness bycasting a lining therein. v

2. The method of salvaging a spent printing cylinder having a keyextending longitudinally therethrough which comprises restoring thecylinder to substantially its original outside diameter withoutdestroying the key, and then restoring the printing wall of the cylinderto substantially its original thickness by casting a lining therein andabout said key.

3. The method of salvaging a printing cylinder having a standard mandrelhole and a key extending longitudinally therethrough which comprisesexpanding the cylinder without destroying the key. centrally positioningwithin the cylinder a core which is of the same size as the standardmandrel hole and which is provided with a longitudinally disposed slot,positioning a short section of a preformed key in one end of said slot,pouring molten metal between `the core and the cylinder, allowing themetal to harden and then removing the core.

; 4 The method of salvaging a printing cylinder having a standardmandrel hole and a key extending longitudinally therethrough, whichcomprises, expanding the cylinder without destroying the key, cutting anumber of grooves in the key, centrally positioning within the expandedcylinder a core-which is of substantially -the same size as the standardmandrel hole and which isv provided with a longitudinal slot, pouringmolten metal between the core and the cylinder, allowing the metal toharden and then removing the core.

5. 'I'he method of salvaging a printing cylinder having a standardmandrel hole and a key extending longitudinally therethrough, whichcomprises, expanding `the cylinder without destroying the key, cutting anumber of retaining grooves in the key, centrally positioning within thecylinder a core which isof the same size as the standard mandrel holeand whch'is provided with a longitudinally disposed keyway, positioninga short section of a preformed key in one end of the keyway, pouringmolten metal between the core and the cylinder, allowing the metal toharden and then removing the core.

6. A printing' cylinder `comprising an outer shell of copper having anumber of key'sections. and a lining therefor within which said sectionsare embedded, said lining having a standard mandrel hole and a keyextending therethrough and said key being formed at one end by apreformed key section embedded in the lining.

7. Themethod of salvaging a spent printing cylinder which comprisesforcing an expander element through the cylinder to increase thediameter thereof, and then providing the expanded cylinder with a liningthrough which a mandrel hole extends.

u. The method of salvaging a spent printing,

cylinder which comprises forcing an expander element through thecylinderto restore the cyl- Inder to substantially its originaloutside diameter.and then providing the expanded cylinder awww with a lining to restorethe printing wall to substantially its original thickness.

9. The method of salvaging a spent println cylinder having a keyextending longitudinally therethrough which comprises forcing anexpander element through the cylinder to increase the diameter thereofwithout destroying the key, and then providing the expanded cylinderwith a lining in which the key is embedded.

10. The method of salvaging a spent printing cylinder which comprisesforcing an expander element through the cylinder to increase thediameter thereof during which the length of the cylinder may heincreased, lining the cylinder to increase the thickness of the printingwall, and restoring the cylinder to its original length.

11. The method of salvaging a spent printing cylinder which comprisesforcing an expander element through the cylinder to increase thediameter thereof, and then casting a lining in said expanded cylinderwhile it is maintained at an elevated temperature.

12. A printing cylinder comprising a seamless outer shell of distortedmetal having properties suitable to provide a printingsurface, a liningof undistorted metal for said shell, and means for mechanicallyanchoring said lining to said shell.

13. A printing cylinder comprising a seamless outer shell of distortedmetal having a. key extending longitudinally therethrough, and a lin-`ing of undistorted metal for said shell in which prevent relativemovement between the shell and the lining during a printing operation.

OWEN R. HUGGINS.

